Problem: $ { \left[\begin{array}{rr}{1} & {2} \\ {2} & {2} \\ {2} & {0}\end{array}\right]-\left[\begin{array}{rr}{3} & {2} \\ {0} & {3} \\ {1} & {-1}\end{array}\right] = {?} } $
Explanation: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{1}-{3} & {2}-{2} \\ {2}-{0} & {2}-{3} \\ {2}-{1} & {0}-{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-2} & {0} \\ {2} & {-1} \\ {1} & {1}\end{array}\right]}$